Field-Free Magnetization Switching in a Ferromagnetic Single Layer through Multiple Inversion Asymmetry Engineering
Qikun Huang, Chaoshuai Guan, Yibo Fan, Xiaonan Zhao, Xiang Han, Yanan Dong, Xuejie Xie, Tie Zhou, Lihui Bai, Yong Peng, Yufeng Tian, Shishen Yan
Abstract
A simple, reliable, and self-switchable spin–orbit torque (SOT)-induced magnetization switching in a ferromagnetic single layer is needed for the development of next generation fully electrical controllable spintronic devices. In this work, field-free SOT-induced magnetization switching in a CoPt single layer is realized by broken multiple inversion symmetry through simultaneously introducing both oblique sputtering and a vertical composition gradient. A quantitative analysis indicates that multiple inversion asymmetries can produce dynamical bias fields along both z- and x-axes, leading to the observed field-free deterministic magnetization switching. Our study provides a method to accomplish fully electrical manipulation of magnetization in a ferromagnetic single layer without the external magnetic field and auxiliary heavy metal layer, enabling flexible design for future spin–orbit torque-based memory and logic devices.